Dr James Moultrie considers how manufacturers could be using new additive manufacturing technologies more effectively for series production of components.
Additive manufacturing (AM) has the potential to transform not just the way things are made but every aspect of how firms go about meeting their customers’ needs, whether through customisation, supply chain reconfiguration or wholesale business model innovation.
The Institute for Manufacturing at University of Cambridge has been working with industrial partners to develop a set of design guidelines that will help accelerate the uptake of AM as an economically viable production process and help designers understand how they can take advantage of the capabilities of AM technologies.
While it is possible to use AM to produce almost any component you can imagine, if the aim is to produce parts efficiently – in 10 minutes rather than 10 hours – there are certain principles to follow.
As a result, the IfM has begun to codify some of these design principles, which aim to help with the design of components which take better advantage of AM for series production.
Design for additive manufacturing: some new rules
1. Use the least material possible
AM is often a slow process, and comparatively simple parts can take many hours to produce. The less material used, the less time taken. Therefore, shape optimisation to eliminate excess material might be beneficial, reducing time, resources and cost.
2. Don’t print air
As the print head moves around the build volume, time and therefore cost can be minimised if the shape is flat, has a low z-height and the shape isn’t an open or enclosed box.
3. Define and connect functional surfaces
Challenge conventional ways of thinking – it can be advantageous first to define the functional surfaces of a part and seek to join them in the most efficient way possible.
4. Minimise shape complexity
Despite the claims that anything can be printed with AM, complexity is expensive. The more changes of direction and greater distance the print head has to move, the longer a part typically takes to print.
5. Minimise infill
In certain AM processes, ‘solid’ shapes are not solid and comprise a surface that encases ‘infill’ (a honeycomb lattice) which holds the shape together. This infill is a form of ‘support structure’ and serves little functional purpose, while taking a long time to print. Thus, reducing or eliminating the need for infill can make parts more cost effective. This often results in parts that are more ‘shell’ like.
6. Minimise support material
Support material is generally indicative of a part that has not been optimised for AM production.
7. Enable nesting and tessellation in the build volume
Parts which ‘nest’ together – such as a stack of plastic cups with each nesting inside the next – enable multiple parts to be built simultaneously. Similarly, parts that tessellate allow for more components to be created at the same time. Again, this is more time and cost efficient.
This is an extract from a longer article which offers a real-world case study of putting these design rules into practice – Using additive manufacturing beyond prototypes
